A flattened variant's HoldsIds is read off the document re-resolved against the post-batch base, not carried from the
variant or from the document the flatten was planned against. The conditional commit onto a file decides by the same
rule as the unconditional commit (ids in the records the file will hold, ids only this cache minted excepted, a marked
file staying marked). The directory manifest's header choice moves beside FormatFor. Pins the three-batch flatten
probe on the commit and flush paths, the conditional commit, the last id leaving, an id-bearing override that is not
the last, and a failed CultMesh write giving its ids back.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
6a7d17bdda